分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: We briefly review the lepton flavor violating Z-decays at GigaZ as a probe of supersymmetry by focusing on Z → lilj in two representative supersymmetric models: the minimal supersymmetric model without R-parity and the supersymmetric seesaw model. We conclude that under the current experimental constraints from LEP and li → ljγ, these rare decays can still be enhanced to reach the sensitivity of the GigaZ. Therefore, supersymmetry can be probed via these decays at GigaZ.
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: In this talk we briefly review the current CDMS/XENON constraints on the neutralino dark matter in three popular supersymmetric models: the minimal (MSSM), the next-to-minimal (NMSSM) and the nearly minimal (nMSSM). The constraints from the dark matter re
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: Since the top quark FCNC processes are extremely supressed in the Standard Model (SM) but could be greatly enhanced in some new physics models, they could serve as a smoking gun for new physics hunting at the LHC. In this brief review we summarize the new
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: The left-right twin Higgs model predicts a light stable scalar \hat{S}, which is a candidate for WIMP dark matter. We study its scattering on nucleon and find that the cross section is below the CDMS II upper bound but can reach the SuperCDMS sensitivity.
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: Motivated by recent studies of intersecting D-brane systems in critical string theory and phenomenological AdS/QCD models, we present a detailed analysis for the vector and scalar fluctuations in a non-critical holographic QCD model in the high temperatur
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: Little Higgs theory naturally predicts a light Higgs boson whose most important discovery channel at the LHC is the di-photon signal pp→h→γγpp→h→γγpp\to h\to \gamma\gamma. In this work we perform a comparative study for this signal in some typical little
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: Motivated by recent studies of deep inelastic scattering (DIS) off the N=4N=4\mathcal{N}=4 super-Yang-Mills (SYM) plasma, holographically dual to AdS5×S5AdS5×S5AdS_5\times S^5 black hole, we in this note use the spacelike flavor current to probe the inter
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: Taking into account the mixing effects between left- and right-handed top-squarks, we calculate the genuine supersymmetric eletroweak correction to top quark pro- duction at the Tevatron in the minimal supersymmetric model. The analytic ex- pressions of the corrections to both the parton level cross section and the total hadronic cross section are presented. Some numerical examples are also given to show the size of the corrections.
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: We listed all possible dimension-six CP-violating SUc(3)×SUL(2)×UY(1)SUc(3)×SUL(2)×UY(1)SU_c(3)\times SU_L(2)\times U_Y(1) invariant operators involving the third-family quarks, which can be generated by new physics at a higher energy scale. The expressio
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: The light stop if produced in hadron colliders in the form of t ̃ t ̄ ̃ pair and decaying through the likely decay chain t ̃ →χ ̃+bfollowedbyχ ̃+ →χ ̃0ff ̄′,can mimic closely a 1 top quark event when the mass of the stop is close to that of the top quark. Because of the much lower production rate, the stop event can be buried under the top quark event sample. In order to uncover the stop event, specific selection cuts need to be applied. Through Monte Carlo simulation with suitable kinematic cuts, we found that such stop event can be extracted from the top quark sample and detected by the top counting experiments in the upcoming upgraded Tevatron and LHC. However, because of the small statistics of the Run 1 of the Tevatron, the stop signal remains hidden at Run 1.
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: Rare decays B_{s,d}-->mu^+ mu^- are evaluated in technicolor model with scalars. R_b is revisited to constrain the model parameter space. It is found that restriction on f/f' arising from R_b which was not considered in previous studies requires f/f' no l
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: Higgs boson productions at the LHC will serve as a sensitive probe of various little Higgs models. In this work we comparatively study two littlest Higgs models with different T-parity constructions through examining their effects in three production proc
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: We study the direct mediation of metastable supersymmetry breaking by a Φ2Φ2\Phi^2 (ΦΦ\Phi is the meson field) deformation to the ISS model and extend it by splitting ΦΦ\Phi into two parts and gauging the flavor symmetry. We find that with such an extensi
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: The Zbb coupling determined from the Z-pole measurements at LEP/SLD shows an about 3-sigma deviation from the SM prediction, which would signal the presence of new physics in association with the Zbb coupling. In this work we give a comprehensive study fo
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: The next-to-minimal supersymmetric model (NMSSM) with a large lambda (the mixing parameter between the singlet and doublet Higgs fields) is well motivated since it can significantly push up the upper bound on the SM-like Higgs boson mass to solve the litt
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-28
摘要: We study the Higgs boson decays and production via gluon fusion at the LHC as a probe of two typical littlest Higgs models which introduce a top quark partner with different (even and odd) T-parity to cancel the Higgs mass quadratic divergence contributed
分类: 分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-12-27
摘要: In this note we revisit the SUSY effects in Rb under current experimental constraints including the LHC Higgs data, the B -physics measurements, the dark matter relic density and direct detection limits, as well as the precision electroweak data. We first
分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-05-16
摘要: We list all possible dimension-six CP-violating SUc(3) x SUL(2) x U-Y(1)-invariant operators involving the third-family quarks, which can be generated by new physics at a higher energy scale. The expressions of these operators after electroweak symmetry breaking and the induced effective couplings Wt (b) over bar,Xb (b) over bar, and Xt (t) over bar (X = Z,gamma,g,H) are also presented. We evaluate sample contributions of these operators to CP-odd asymmetries of transverse polarization of the top quark in single top quark production at the upgraded Fermilab Tevatron, the same polarization effect in top-quark-top-antiquark pair production at the NLC, and the CP-odd observables of momentum correlations among the top quark decay products at the NLC. The energy and luminosity sensitivity in probing this CP-violating new physics is also studied.
分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-05-15
摘要: In the minimal supersymmetric standard model extended by including right-handed neutrinos with seesaw mechanism, the neutrino Yukaka couplings can be as large as the top-quark Yukawa couplings and thus the neutrino/sneutrino may cause sizable effects in Higgs boson self-energy loops. Our explicit one-loop calculations show that the neutrino/sneutrino effects may have an opposite sign to top/stop effects and thus lighten the lightest Higgs boson. If the soft-breaking mass of the right-handed neutrino is very large (at the order of Majorana mass scale), such as in the split-supersymmetry (SUSY) scenario, the effects can lower the lightest Higgs boson mass by a few tens of GeV. So the Higgs mass bound of about 150 GeV in split-SUSY may be lowered significantly if right-handed neutrinos come into play with seesaw mechanism.
分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-05-15
摘要: In the Affleck-Dine mechanism of baryogenesis, nontopological solitons called Q-balls can be formed. In this work we propose that such Q-balls decay during the BBN era and study the cosmological consequence of such late decays. We find that the late-decaying baryonic Q-balls with lifetime of about 10(3) s can provide a new developing mechanism for the BBN through a rolling baryon-to-photon ratio eta, which can naturally explain the discrepancy of the BBN prediction with the WMAP data on Li-7 abundance. For the late-decaying leptonic Q-balls with lifetime of about 10(6) s, we find that their decay product, gravitinos, can serve as a dark matter candidate and give an explanation for the approximate equality of dark and baryon matter densities. (C) 2004 Elsevier B.V. All rights reserved.